CART Thermochemistry and Energy

Question 1

What is the term for the heat released or absorbed during a chemical reaction at constant pressure?

Accepted Answer

Enthalpy change (ΔH)

Answer

Entropy change (ΔS)

Answer

Gibbs free energy (ΔG)

Answer

Internal energy (ΔU)

Question 2

A reaction with a negative ΔH value is classified as:

Accepted Answer

Exothermic

Answer

Endothermic

Answer

Isothermal

Answer

Adiabatic

Question 3

Which law states that the enthalpy of a reaction is the same whether it occurs in one step or multiple steps?

Accepted Answer

Hess's Law

Answer

Law of Conservation of Energy

Answer

Le Chatelier's Principle

Answer

Avogadro's Law

Question 4

The specific heat capacity of water is 4.18 J/(g·°C). How much heat is needed to raise 50 g of water by 10°C?

Accepted Answer

2090 J

Answer

418 J

Answer

209 J

Answer

4180 J

Question 5

Which of the following processes is endothermic?

Accepted Answer

Melting of ice

Answer

Condensation of steam

Answer

Freezing of water

Answer

Combustion of methane

Question 6

Standard enthalpy of formation (ΔH°f) for an element in its standard state is:

Accepted Answer

0 kJ/mol

Answer

1 kJ/mol

Answer

–1 kJ/mol

Answer

Varies by element